39 lines
1.7 KiB
Markdown
39 lines
1.7 KiB
Markdown
|
---
|
||
|
title: "Rust's Impure Path"
|
||
|
date: 2022-10-30T12:47:41-05:00
|
||
|
languages: ["rust"]
|
||
|
tags: ["rust"]
|
||
|
---
|
||
|
|
||
|
I work on [garbage], a project that touches the filesystem a lot. Because of
|
||
|
this, I'd really like to control when and where these filesystem accesses
|
||
|
happen.
|
||
|
|
||
|
[garbage]: https://git.sr.ht/~mzhang/garbage
|
||
|
|
||
|
The Rust standard library has a `fs` module, which I expect to _exclusively_
|
||
|
contain filesystem access primitives. But actually a lot of the functionality
|
||
|
also gets leaked into `std::path::Path`.
|
||
|
|
||
|
In my ideal world, `Path` only deals with the data in a path, not its
|
||
|
interaction with the filesystem. So it should never be able to check whether or
|
||
|
not a path [exists], for example, or if a path [is a symlink][is_symlink]. Those
|
||
|
should be delegated to something within `fs`.
|
||
|
|
||
|
[exists]: https://doc.rust-lang.org/stable/std/path/struct.Path.html#method.exists
|
||
|
[is_symlink]: https://doc.rust-lang.org/stable/std/path/struct.Path.html#method.is_symlink
|
||
|
|
||
|
In addition, many of these functions automatically resolve symlinks, without
|
||
|
built-in ways of achieving the same functionality without resolving symlinks, so
|
||
|
I ended up having to fill those in myself. For example, I really just expect
|
||
|
[`canonicalize`] to be an in-memory manipulation of path components.
|
||
|
|
||
|
[`canonicalize`]: https://doc.rust-lang.org/stable/std/path/struct.Path.html#method.canonicalize
|
||
|
|
||
|
Honestly, I've got to give it to Python's [pathlib], which solves the problems I
|
||
|
noted above. It splits the path API into `Path` and `PurePath`, the latter of
|
||
|
which does not make any IO accesses. It also provides non-symlink-resolving and
|
||
|
symlink-resolving variants of converting to absolute paths.
|
||
|
|
||
|
[pathlib]: https://docs.python.org/3/library/pathlib.html
|